BP puck pump

[toster]

So,I have a friend that is a machinist, and I have been wanting to have him make aBP puck pump. I have been thinking of something like THIS.I was thinking it would be nice to have a "fill to" line, and a"press to line" marked in the pump. Kind of like a Go, No Go line. Ifi want to get to the ideal 1.7 gm/cc (I think that is correct, off the top)puck, and my ID of my tooling will either be 2”or 2.5” what would volume wouldI need to have the meal powder take up (fill to line) and how far up would thismark would be? (think of a syringe back at the 5cc mark) Then, if I wanted the finished puck to be ¼in think (or should I go thicker?) where the No Go line be (guessing ¼ in upfrom the top of the sleeve with the plunger fully inserted in to the sleevethat only makes sense)? …. Ugh that 7^th grade geometry class…. Ishould have been paying attention!! Any suggestions on this? I have access to a20 ton hydraulic air integrated press so maybe I should go larger. I justdidn’t know how much pressure I would have to exert on the 2.5 pump, and don’twant to go too large with the tooling.

 

[Bonny]

So,I have a friend that is a machinist, and I have been wanting to have him make aBP puck pump. I have been thinking of something like THIS.I was thinking it would be nice to have a "fill to" line, and a"press to line" marked in the pump. Kind of like a Go, No Go line. Ifi want to get to the ideal 1.7 gm/cc (I think that is correct, off the top)puck, and my ID of my tooling will either be 2”or 2.5” what would volume wouldI need to have the meal powder take up (fill to line) and how far up would thismark would be? (think of a syringe back at the 5cc mark) Then, if I wanted the finished puck to be ¼in think (or should I go thicker?) where the No Go line be (guessing ¼ in upfrom the top of the sleeve with the plunger fully inserted in to the sleevethat only makes sense)? …. Ugh that 7^th grade geometry class…. Ishould have been paying attention!! Any suggestions on this? I have access to a20 ton hydraulic air integrated press so maybe I should go larger. I justdidn’t know how much pressure I would have to exert on the 2.5 pump, and don’twant to go too large with the tooling.

 

 

 

The calculations needed are on the forum here somewhere... It's been awhile since I've seen them though. Once you do the math, a given weight of BP (before adding water) pressed to the "press to line" would work. The fill line (volumetric loading) would not be accurate as the BP could be "fluffier" in one batch than the next.

The pressure doesn't matter, as long as you can press the bp to the right density.

1/4" pucks are a good thickness for corning. Mine vary between 1/4 and 3/4", and I've never bothered to check density. Not likely optimum, but my BP lifts just fine.

[superscifi12]

So,I have a friend that is a machinist, and I have been wanting to have him make aBP puck pump. I have been thinking of something like THIS.I was thinking it would be nice to have a "fill to" line, and a"press to line" marked in the pump. Kind of like a Go, No Go line. Ifi want to get to the ideal 1.7 gm/cc (I think that is correct, off the top)puck, and my ID of my tooling will either be 2"or 2.5" what would volume wouldI need to have the meal powder take up (fill to line) and how far up would thismark would be? (think of a syringe back at the 5cc mark) Then, if I wanted the finished puck to be ¼in think (or should I go thicker?) where the No Go line be (guessing ¼ in upfrom the top of the sleeve with the plunger fully inserted in to the sleevethat only makes sense)? …. Ugh that 7^th grade geometry class…. Ishould have been paying attention!! Any suggestions on this? I have access to a20 ton hydraulic air integrated press so maybe I should go larger. I justdidn't know how much pressure I would have to exert on the 2.5 pump, and don'twant to go too large with the tooling.

 

 

 

 

One of the ideas in corning/pressing BP is the ability to measure by using volume instead of by weight. So till you press it you can't have a "fill to" line. A press to line only works if you press the same amount by weight.

 

A 2.000 puck that is .250 thick would have a volume of 0.7855 cu in would have to weigh 0.7718813 oz to make the 1.7g/cc (0.982662342 ounce/cubic inch) The reason of United States customary system is that I am a machinist and at the shop I work at we do nothing in metric. If we get a metric job we convert it to United States customary system (inches).

[toster]

One of the ideas in corning/pressing BP is the ability to measure by using volume instead of by weight. So till you press it you can't have a "fill to" line. A press to line only works if you press the same amount by weight.

 

A 2.000 puck that is .250 thick would have a volume of 0.7855 cu in would have to weigh 0.7718813 oz to make the 1.7g/cc (0.982662342 ounce/cubic inch) The reason of United States customary system is that I am a machinist and at the shop I work at we do nothing in metric. If we get a metric job we convert it to United States customary system (inches).

 

Bonny, I wondered about the density of the meal powder being consistent.....

 

SuperSifi12,

 

So the unpacked volume doesn't matter, just put in .7719 oz and press it to 1/4 in thick. Correct? I think I follow your calculations? (I know I’m nerd like that)

 

 

 

Let’s see if I get this correct Volume of a cylinder = Pie r^2 * h

 

V= 3.1415926 * 1^2 * .25

 

V=.7853981634 cu

 

 

 

If I want the density to be 0.982662342 ounce/cubic inch take that times the volume, and get the .7717811986 oz

 

 

 

So, all I need is a STOP pressing the crap out of it line!! Now off to Google.Sketchup to draw it up! Thanks!

 

 

[FREAKYDUTCHMEN]

To make the process easier it's better to only look at the pressure you're pressing. I only press up to a certain amount of pressure and don't calculate and weight everything. The pressure is my standard, the density is not important as long as it's always the same. 1.7 is not making the blackpowder the fastest, it's only a standard. You'll see it's harder to make a higher density blackpowder with a light weight charcoal than if you do with a heavier charcoal.

Try to keep things simple, this will save you a lot of time.

[superscifi12]

To make the process easier it's better to only look at the pressure you're pressing. I only press up to a certain amount of pressure and don't calculate and weight everything. The pressure is my standard, the density is not important as long as it's always the same. 1.7 is not making the blackpowder the fastest, it's only a standard. You'll see it's harder to make a higher density blackpowder with a light weight charcoal than if you do with a heavier charcoal.

Try to keep things simple, this will save you a lot of time.

 

As long as he makes consistent BP that would work. Obviously it wouldn't be 0.982662342 ounce/cubic inch(unless you get lucky), but if that doesn't matter to you then it would work. I will use my BP in a flintlock also so I need consistent density to keep the loads the same with commercial powder or my own.

[Bonny]

To make the process easier it's better to only look at the pressure you're pressing. I only press up to a certain amount of pressure and don't calculate and weight everything. The pressure is my standard, the density is not important as long as it's always the same. 1.7 is not making the blackpowder the fastest, it's only a standard. You'll see it's harder to make a higher density blackpowder with a light weight charcoal than if you do with a heavier charcoal.

Try to keep things simple, this will save you a lot of time.

 

 

As long as he makes consistent BP that would work. Obviously it wouldn't be 0.982662342 ounce/cubic inch(unless you get lucky), but if that doesn't matter to you then it would work. I will use my BP in a flintlock also so I need consistent density to keep the loads the same with commercial powder or my own.

 

 

As noted above consistency is the key. I think for a flintlock more accuracy is needed than for lifting shells. As Freaky said, try to keep it simple. In my case I press approx the same amount per batch. I make 5 3" pucks at a time with a 12 ton jack. I do have a gauge, but I also allow the powder to dwell under pressure for a "similar" amount of time before pumping the jack again. The dwell time IMO is very important to allow the powder to settle into place. I repress 2 times.

[superscifi12]

To make the process easier it's better to only look at the pressure you're pressing. I only press up to a certain amount of pressure and don't calculate and weight everything. The pressure is my standard, the density is not important as long as it's always the same. 1.7 is not making the blackpowder the fastest, it's only a standard. You'll see it's harder to make a higher density blackpowder with a light weight charcoal than if you do with a heavier charcoal.

Try to keep things simple, this will save you a lot of time.

 

I was thinking about this while at work today and where does the 1.7g/cc come from? 1.73g/cc is 1.000003443oz/in3 Is the standard a conversion from american standard to metric? The reason I propose this is that most of the scales that are commonly used, based on other sites and forums, don't read .01 grams and to round you would just drop the .03.

[dagabu]

The dwell time IMO is very important to allow the powder to settle into place. I repress 2 times.

 

Yes, do keep the dwell time the same from puck to puck. IMHO, re-pressing up to 5 times (a few seconds between pressing) makes a huge difference. 30 seconds overall is my standard.

 

-dag

[Peret]

I was thinking about this while at work today and where does the 1.7g/cc come from?

There are published curves for burn speed versus pressing density. I found this one in Russell: The Chemistry of Fireworks. You can see that the burning time ramps up sharply just after 1.7 g/cc, so that is about as dense as you can go and still have a fast powder.

[toster]

I think we messed up. I got the tooling. It is great. But when going back through the numbers I see that we used a radius of 1, not 2. ( I had the press made 2.5 in)

 

So lets try this again:

 

r=2.5in

h=0.25in

pie=3.1415926

optimum density 0.982662342 ounce/cubic inch

 

V=4.908738438 ci

 

oz for Optimum=4.823632409 oz

 

1 ounce = 28.3495231 grams

 

grams for optimum136.7476784 grams

 

But remember that is "dry" weight. So with 10% water added I would need 150.42 grams of material.

 

Correct???

 

One of the ideas in corning/pressing BP is the ability to measure by using volume instead of by weight. So till you press it you can't have a "fill to" line. A press to line only works if you press the same amount by weight.

 

A 2.000 puck that is .250 thick would have a volume of 0.7855 cu in would have to weigh 0.7718813 oz to make the 1.7g/cc (0.982662342 ounce/cubic inch) The reason of United States customary system is that I am a machinist and at the shop I work at we do nothing in metric. If we get a metric job we convert it to United States customary system (inches).

Edited May 19, 2011 by toster

[toster]

Here are some pics of the BP Puck Tooling I had made.

 

http://i1022.photobucket.com/albums/af342/toster01/photo1.jpg

 

Four pieces 3/4 in rings, sleeve is 5 in and plunger is 7in height.

 

http://i1022.photobucket.com/albums/af342/toster01/photo2-1.jpg

 

All put together, setting on the solid ring. The hollow ring is to push out the puck.

 

http://i1022.photobucket.com/albums/af342/toster01/photo4.jpg

 

In the press ready to go. (i know no blast shield) I was not pressing. Just testing things out.

 

http://i1022.photobucket.com/albums/af342/toster01/photo3.jpg

 

Close up of the push out ring, and grove on the bottom of the sleave.

[Mumbles]

The tooling looks great.

 

I think there is a slight error in your math. It seems you forgot to multiply by the height. It will work if you want to press 1inch thick pucks though. I'll be rounding everything off to a few decimals for reporting if you don't mind, but I'm keeping the full string for the real calculations.

 

1.25in * 1.25in * 3.1415 = 4.908 sq. in.

 

4.908 sq in * 0.25 in tall = 1.23 cubic in.

 

1.23 cu. in * .983 oz/cu. in = 1.206 oz

 

To get the wet weight, multiply by whatever factor you're wetting. Depending on your press, you may find 10% to be too wet. I believe most operate in the 4-6 or 7% water range.

 

10% would be 1.1 = 1.327oz moist comp

 

Are you planning to press one puck at a time, or do several at a time with spacers?

[toster]

Mumbles, thanks for the double check, I guess my brain wasn't working last night. ( I used the diamater 2.5, not the radius of 1.25!) I was just going to do one at a time, never thought about a spacer.....hmmmm....

[FrankRizzo]

Mumbles, thanks for the double check, I guess my brain wasn't working last night. ( I used the diamater 2.5, not the radius of 1.25!) I was just going to do one at a time, never thought about a spacer.....hmmmm....

 

Toaster - DON'T USE YOUR PRESS quite yet. The missing blast shield serves a secondary function of keeping that type of press frame (Dan Williams design) from bending. The two threaded rods provide a good amount of strength up and down, but they are quite flimsy toward or away from you. Without some stiffening, a slight amount of tool misalignment will start a bow, and it will get progressively worse. Eventually, you'll start bending rocket spindles or kicking out tooling under pressure. Do yourself a favor, and don't use the press until you get it stiffened up with a shield.

 

A real simple design would be to use a wooden panel of 3/4" OSB with a window cut out in the center, and a piece of 1/2" Lexan glued to the press-facing side with liquid nails. You'd need to drill two holes in the top and bottom pieces of channel, and use (4) bolts to attach it.

 

http://pyrobin.com/files/osb-1.jpg

 

Lexan scraps can be found really cheap on eBay.

[toster]

thanks for the heads up, I was going to swing by a plastics place here in town tomarrow, and see if they had anything laying around.